Symmetry occurs in many problems in aritifical intelligence. For example, in the n-queens problem, the chessboard can be rotated 90°. As a second example, several machines in a factory might have the same capacity. In a production schedule, we might therefore be able to swap the jobs on machines with the same capacity. As a third example, two people within a company might have the same skills. Given a staff roster, we might therefore be able to interchange these two people. And as a fourth example, when configuring a computer, two memory boards might be identical. We might therefore be able to swap them around without changing the performance of the computer.